Known as the "Res Probe," this novel seafloor instrument is designed to go inside the "throats" of high temperature (up to 480°C) black smoker chimneys to measure the resistivity and temperature of the hydrothermal vent fluids. Resistivity is an analog for chlorinity, measuring the "saltiness" of the vent fluids. Many of the structures at Axial Volcano emit boiling fluids, as reflected by their high temperature and low chlorinity.
During the VISIONS'14 Cruise, a resistitivy-temperature instrument was installed at the hydrothermal vent known as 'Escargo', named because the morphology of the chimney is reminiscent of a snail. A similar instrument has been installed at a vent (Grotto) in the Main Endeavour hydrothermal field for over a year, as part of the Ocean Networks Canada cable array.